<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<img id="qrImg" src=""/>
</body>

<script type="text/javascript" src="js/jquery-1.8.3.min.js"></script>
<script>
    $(function () {
        //截取=后边的东西
        $("#qrImg").attr("src", "https://mp.weixin.qq.com/cgi-bin/showqrcode?ticket=" + location.href.split("=")[1]);
    })

</script>
</html>